This article sets out to determine the association between the reasons why university students in Tanzania select their fields of study and intention to join their respective professions upon completion of their studies. A mixed methods research approach was adopted to study a random sample of 1043 undergraduate students (Male=61%, Female=39%) drawn from four universities. The study found that determinants of career choice and intentions differed significantly with fields of study. Students' intentions to join their prospective careers were more associated with intrinsic than extrinsic factors. Furthermore, students whose degree programmes were their first choices were more likely to re-choose if asked to do so and join their prospective careers than those who joined by chance. The study concludes that when students choose their degree programmes with enough knowledge and interest, they are more likely to enjoy and be committed to the chosen fields of study, hence, satisfaction in their future career.